By way of example, an article with the title “Neue Sendeantenne auf dem Säntis, Schweitz” [New transmitting antenna at S{hacek over (a)}ntis, Switzerland] was published in the magazine for customers of the company Kathrein-Werke KG (December 1997 issue). This article indicates that the transmitting systems comprise transmitting antennas for broadcast radio, television and mobile radio. The high attitude and, associated with this, the extremely low temperatures in winter made it necessary to use a double-walled radome which can be heated, and within which the antenna elements are accommodated.
Comparable antenna devices have been disclosed, although these are generally intended for base stations for the field of mobile radio, so that the radome has a considerably smaller diameter than that in the prior art cited initially.
Prior publications such as these have become known, for example, from DE 202 05 550 U1 or DE 202 18 101 U1. Both prior publications describe a central antenna mount which, according to DE 202 18 101 U1, can also be provided with radially projecting supporting walls, thus forming three sections or 120° angular areas which are offset from one another in the circumferential direction. Conventional antenna devices are mounted in these area, secured to the antenna nylon, and are provided in the factory with a suitable radome, that is to say with their own antenna cover.
The entire arrangement is surrounded by cladding which has a cylindrical cross section, is located on the outside, and which, according to DE 202 18 101 U1, can be formed with a single wall or, according to DE 202 05 550 U1, can likewise be formed with a double wall, as in the prior art cited initially.
The overall physical complexity, including installation on site, but in particular the difficulty in carrying out repairs have been found to be major disadvantages with the last-mentioned antenna systems. Particularly when, for example, components are not just to be replaced but are also intended to be fitted retrospectively, this involves considerable installation effort in order first of all to remove all of the cladding, to retrofit the appropriate components at a high altitude, in order then to fit the cladding once again once the work has been carried out.
An apparatus of this generic type for accommodating sector antennas has been disclosed in DE 101 19 612 A1. The antenna arrangement for holding the sector antennas, and preferably being formed by mobile radio antennas, has a vertically arranged pylon whose upper section has a mounting piece 3 which is formed by a tube. This is an internal mounting tube in the form of a pylon. The sector antennas are mounted on the external circumference of this mounting tube. An enveloping tube which is mounted on the pylon and through which electromagnetic radiation can pass is then provided for the entire arrangement, comprising the internal mounting tube and the sector antennas which are attached to it. This is what is referred to as the radome. The enveloping tube in this case merges without any discontinuities into a vertical tube which forms the lower section of the pylon. The actual pylon thus forms a step transition from the lower vertical tube with a larger diameter to the upper tubular piece of wire with a thinner diameter, with apertures being provided at the step transition formed in this way, through which the cables which lead to the sector antennas are routed.
Since the lower vertical tube which is provided with the large diameter merges without any discontinuities into the upper developing tube, the entire antenna arrangement appears to be effectively clad and concealed.
Another major disadvantage which has been found with the prior art of the generic type, as well, is that, at certain relatively high wind speeds, the entire antenna pylon can resonate in such a way that the radome is fractured.
The exemplary illustrative non-limiting implementations herein overcome the disadvantages of the prior art and provide an improved antenna arrangement.
In fact, it must be regarded as surprising that the exemplary illustrative non-limiting implementations results in a very highly robust antenna arrangement which is in the form of a pylon, with all of the antenna systems being concealed in a tubular radome which can be designed to be extremely thin. This radome can preferably—as with other known systems as well—have a cylindrical cross section, but may also have any other desired horizontal cross section, for example being polygonal with n sides, or being oval etc. Furthermore, the exemplary illustrative non-limiting antenna arrangement is distinguished by having a service zone in which all the relevant adjustment and connection measures can be carried out, without having to dismantle the entire antenna pylon or else having to remove just the entire radome in advance in order to gain access to the components located underneath it.
Furthermore, the exemplary illustrative non-limiting antenna arrangement has a damping device which ensures that the antenna structure, and in particular the radome, cannot resonate at an appropriate wind speed, thus destroying the system or parts of it.
The exemplary illustrative non-limiting antenna system can be constructed such that, underneath the radome, it has antenna elements which, by way of example, transmit directionally in at least two sectors, preferably in three or more sectors. Any desired antenna element devices can be used in this case, which can transmit even with widely differing horizontal beamwidths, for example with a 3 dB beamwidth of 90°, a 3 dB beam width of 60-65°, etc.
Single-polarized, dual-polarized or else circular-polarized antenna elements can be used. Even what are referred to as x-polarized antenna elements and antenna element arrays can be used, whose polarization directions are aligned at angles of +45° and −45° with respect to the horizontal plane or with respect to a vertical plane.
The exemplary illustrative non-limiting antenna arrangement may also have broadband or narrowband antennas and antenna elements. This structure can be designed such that the entire antenna arrangement transmits and receives in only one band or in a number of bands, for example, in two bands. The band structure may also be a broadband structure, such that it covers, for example, not only the 1800 MHz band for example, but also, for example, the 1900 MHz band (as is normally used in the USA) and/or the UMTS band at about 2000 MHz.
The exemplary illustrative non-limiting antenna arrangement and the compact construction furthermore for the first time make it possible to construct an antenna device such as this effectively as an omnidirectional antenna by means of appropriate interconnection in the service zone. In this case, the antenna elements can preferably be adjusted to have a different transmission angle with respect to the horizontal plane, by means of a down-tilt device which can be controlled remotely.
What is referred to as the service zone is preferably located underneath all the antenna elements. In this case, the service zone is preferably constructed such that, when it is in the closed state, it effectively represents an extension to the radome which surrounds the antenna elements. For this purpose, the service zone may have a corresponding housing framework at a suitable axial height and with an appropriate diameter, which has sufficiently large opening in order to provide access to the internal area here. The opening areas can be closed and covered by individual coverage caps or by housing shells which surround the entire antenna pylon, which are preferably located at least approximately in the same circumferential plane as the radome which surrounds the antenna elements, so that, from the outside, this preferably results in a structure in the form of a pylon whose overall surface is a smooth and continuous as possible, without any evidence as to whether any components are accommodated in the interior of this structure and, if so, what components are accommodated there.
The service zone is constructed such that it can be mounted on the blunt head of a pylon, at which the necessary antenna cables which lead to the antenna device end at an interface which is formed in this way. This blunt pylon is to this extent also referred to in the following text as the pylon foot, pylon base or else as the antenna foot or antenna base. When the service zone is open, the appropriate intermediate cables can be installed, thus producing an electrical connection from the cables which end in the antenna foot to the connecting points, which are provided in the upper area of the service zone, for the cables which lead to the antenna elements. Any desired necessary components such as amplifiers etc. can likewise be accommodated in these service zones. The amplifiers may, for example, be what are referred to as TMAs, TMBs etc. Some of the amplifiers or other circuits which also, for example, develop heat which must be dissipated to the outside can be designed and arranged such that a portion of the amplifier housing is at the same time used as a covering cap closing arrangement for the opening in the service zone, so that these devices can optimally emit the heat produced by them to the outside (some of the devices which produce heat thus represent a portion of the outer casing of the antenna arrangement). Since these amplifiers are now located closer to the actual antenna elements (and no longer in a separate base station), not only does this reduce the number of cables which need to be laid from the base station to the antenna elements, but the power which is required for the amplifiers in the antenna arrangement can also be reduced, for example by a factor of 2. Finally, it is possible to reduce not only the number of electrical cables and glass fiber cables which are used but also, possibly, to reduce the diametric cross section that they need to have. The down-tilt adjusting devices which can be remotely controlled, for example motor units which can be driven approximately, can also be accommodated, for example, in the service zone and then drive the plastic shifters (which are located within the radome) in order to set the different down-tilt angles, for example via a transmission linkage.
However, if necessary, not just one but also a second or three or more service zones which are arranged axially one above the other can be provided, and these can also be retrofitted as required as autonomous modules. A single service zone, which is created in the factory, can just as well be provided having, for example, an axially greater height and, in consequence, itself always providing sufficient space to allow additional components to be accommodated, even retrospectively.
The service zone can preferably be fixed and detached via bolt connections such that, even in a state when it is secured by the bolt connection, the service zone, and hence the pylon structure which is located above it, can carry out an axial rotary movement. This allows the antenna elements to be aligned appropriately.